The present invention relates to evaporative elements and cartridges for use in humidifiers, evaporative coolers and the like. The invention specifically relates to paper evaporative elements.
For many years humidifiers have been manufactured and sold having replaceable evaporative elements, sometime also known as cartridges. The purpose of the evaporative element is to spread water over a large surface area to promote evaporation of the water into the air when air is directed over and through the element. The evaporative element may also perform a subsidiary function of filtering the air and/or water. It is well recognized in the art that it is desirable to have an element, through which air may freely pass, having a large surface area. It is also well known to make the evaporative element from materials that will promote capillary or wicking action to absorb and spread the water throughout the evaporative element. The evaporative element should be made of materials and with a configuration sufficient to maintain structural integrity of the evaporative element when it is subjected to prolonged use in water, heat and air flow conditions.
To meet these objectives, the art has developed several types of evaporative elements. One type is slit and expanded metal element. U.S. Pat. No. 3,878,594 issued to Carrier Corporation illustrates one such element. The slit and expanded metal element is made by forming a stack or bundle of layers of slit and expanded metal, by well known techniques. The element is used by trickling water downwardly through the element. The slit and expanded metal inherently consists of a lattice of bridges and strings set at inclined angles as a result of the expansion process. These inclined bridges and strings act as baffles to catch, divert and spread the water throughout the element. The advantages of this type of element is that they are durable and inexpensively manufactured. The disadvantage of the expanded metal units are that metal has very low absorption and capillary action properties.
Another well known evaporative element is a paper element. U.S. Pat. No. 4,822,533 issued to Emerson Electric Company illustrates a paper evaporative element. Paper elements have the advantage of better absorption and capillary action properties. However, they are considerably more expensive to manufacture because specialized paper folding equipment is typically needed. Furthermore, paper elements often lack sufficient structural strength due to prolonged exposure to water and air flow if constructed by more simplistic techniques.
Accordingly, there is in the art an ongoing need for an evaporation element that has high water absorption and capillary action, good structural integrity and which may be economically manufactured. It is therefore the object of the invention to satisfy these needs.